Nattokinase Does Not Raise Blood Pressure
Nattokinase supplementation actually lowers blood pressure rather than raising it, and can be safely used in adults with pre-existing hypertension or cardiovascular disease.
Evidence for Blood Pressure Reduction
The research evidence consistently demonstrates that nattokinase reduces blood pressure in hypertensive populations:
A 2008 randomized controlled trial showed nattokinase (2,000 FU daily for 8 weeks) reduced systolic blood pressure by 5.55 mmHg and diastolic blood pressure by 2.84 mmHg compared to placebo in subjects with pre-hypertension or stage 1 hypertension 1.
A 2023 meta-analysis of six studies with 546 participants confirmed that nattokinase supplementation significantly reduced systolic blood pressure (mean difference -3.45 mmHg) and diastolic blood pressure (mean difference -2.32 mmHg) compared to placebo 2.
A 2016 North American multicenter trial demonstrated that 100 mg nattokinase daily for 8 weeks reduced diastolic blood pressure from 87 mmHg to 84 mmHg overall, with particularly robust effects in males (86 mmHg to 81 mmHg) 3.
Mechanism of Action
The blood pressure-lowering effect appears to be mediated through:
Reduction in plasma renin activity, with the 2008 trial showing a net decrease of 1.17 ng/mL/h in the nattokinase group compared to controls 1.
Decreased von Willebrand factor levels, particularly in females, suggesting improved endothelial function 3.
Reduction in coagulation factors (fibrinogen decreased 7-10%, factor VII decreased 7-14%, factor VIII decreased 17-19%) across healthy, cardiovascular risk, and dialysis populations 4.
Safety Profile in Hypertensive Populations
No significant adverse events were reported in any of the clinical trials, including studies specifically enrolling patients with cardiovascular risk factors 1, 2, 4, 3.
Important Clinical Context
While nattokinase lowers blood pressure, one long-term study (median 3 years) found no effect on subclinical atherosclerosis progression measured by carotid intima-media thickness in healthy individuals at low cardiovascular risk 5. This suggests nattokinase's primary benefit is blood pressure reduction rather than direct anti-atherosclerotic effects.
Practical Recommendation
For adults with pre-existing hypertension or cardiovascular disease taking standard antihypertensive medications per guidelines 6:
Nattokinase supplementation (2,000 FU or 100 mg daily) will not raise blood pressure and may provide additional modest blood pressure reduction of 3-6 mmHg systolic and 2-3 mmHg diastolic 1, 2, 3.
Monitor blood pressure after initiating nattokinase to assess for additive hypotensive effects when combined with standard antihypertensive therapy 6.
The supplement should not replace guideline-directed medical therapy with thiazide diuretics, calcium-channel blockers, ACE inhibitors, or angiotensin-receptor blockers, which remain first-line treatment 6.